import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		double d = 1.299038105676657;
		for (int z = 0; z < t; z++) {
			int r = sc.nextInt();
			double ans = r * r * d;
			System.out.println(ans);
		}
		sc.close();

		
	}
}